Generate verbose syntax from regexp

[Anton Komarev]

It would be great to have inverse behavior.

User provides:

/^([A-Z0-9._%+-])+@[A-Z0-9.-]+\.[A-Z]{2,}$/i

Output:

begin with any of (digit, letter, one of "._%+-") once or more,
literally "@",
any of (digit, letter, one of ".-") once or more,
literally ".",
letter at least 2,
must end, case insensitive

[Karim Geiger]

Duplicate of #9